M.Sc. / During the last decade, Cape Wagtails (Motacilla capensis) have been observed with several forms of feet abnormalities, such as missing toes and clubbed feet. The aim of this research was to find the reason for these abnormalities. The initial hypothesis was that ‘Feet abnormalities in the Cape Wagtail (M. capensis) are caused by the internal action of contaminants (e.g. pesticides and metals) through direct contact and/or secondary poisoning’. Wagtails were caught with mist nets and/or ground traps depending on the area and accessibility of the sampling sites. Wagtails with feet abnormalities, as well as those without, were caught at six localities around South Africa. Indicators of pollutant exposure and effect were studied. The bioaccumulation of certain metals (measures of exposure) in the feathers such as aluminium (Al), arsenic (As), cadmium (Cd), chromium (Cr), cobalt (Co), copper (Cu), iron (Fe), Pb, nickel (Ni), manganese (Mn), silver (Ag), strontium (Sr) and zinc (Zn) and Al, As, calcium (Ca), Cd, Cr, Co, Cu, Fe, Pb, Ni, Mn, Ag and Zn in the blood plasma were analyzed on the Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Biomarker testing (measures of effect) was carried out in the blood such as acetylcholinesterase (AChE) which tested for nerve transmission inhibition, ä-aminolevulinic acid dehydratase (ALA-D) which tested for lead (Pb) bioaccumulation, catalase (CAT) which tested for the invasion of oxyradicles and oxidative stress and DNA damage which tested for DNA band length alteration caused by stress due to xenobiotics. Biomarker outcomes and metal analysis results were carried out on a site comparison basis. Acetylcholinesterase, ALA-D and DNA damage were found not to be linked to the occurrence of feet deformities at these sites. However, CAT revealed stress at all the sites which may have indicated the presence of a stress (or stresses) which could have been caused by feet abnormalities or other factors. A non-metric multidimensional scaling graph (NMDS) ordination suggested that biomarkers were not grouped according to sites that had affected birds and those that did not, but were rather assorted. Consequently, few real differences in biomarker responses were noted between healthy and affected birds. Catalase enzyme activity and DNA damage were suggested to be indicative of feet abnormalities although results were not convincing. Secunda displayed the highest concentrations of metals in the feathers when compared to the other sites. Most metals were higher than reference values for contaminated areas and recent South Africanreported concentrations. Almost all of the metals tested at each site exceeded the Ecological Quality iii Objectives (EcoQOs) for metals in bird feathers, based on Weavers (Ploceus sp.) in the Gauteng region. Zinc levels at all the sites posed some concern. Chromium and Ni were suspected to possibly trigger feet and toe abnormalities in Cape Wagtails. Levels of various metals in the plasma were higher at sites that had no deformities. This suggested that these metal concentrations did not cause or influence feet or toe deformities. Calcium levels were found to be lower at sites with affected birds which indicated that the deformities may perhaps be caused by decreased Ca concentrations. Metal concentrations were higher than the uncontaminated reference levels, but were lower than contaminated site reference values. / Prof. V. Wepener

M.Sc. / The recognition of the occurrence, importance and effects of contaminants on food chains and ecosystems has led to the development of biomonitoring programmes that use indicator species to estimate the levels in other parts of the ecosystem. There has been an increased awareness of potential pollution of ecosystems in Gauteng, South Africa, because of increased formal and informal urbanization, industrialization and mining activities. It is essential to obtain clear indications of metal pollution cause-effect relationships at ecosystem level in order to carry out effective management of these ecosystems. The objective was to investigate the application of an ecotoxicologically-based investigation of metals in selected bird species as bioindicators of metal pollution of ecosystems in Gauteng. Three passerine species were used, the Southern Masked Weaver (Ploceus velatus), the Red Bishop (Euplectes orix) and the Red-billed Quelea (Quelea quelea). The sites were selected to represent a theoretical pollution gradient from severely contaminated wetlands in the Vaal Triangle, to moderately contaminated wetlands in the Witwatersrand and Pretoria. A nature reserve in North West Province was chosen as reference site. The sites were Rietvlei in Tshwane, Roodekrans and Olifantsvlei in Johannesburg, Holfontein in the Vaal Triangle and Barberspan in North West Province. Two sampling surveys were carried out, one in 2002 and one in 2005. Feathers were collected for metal analyses. Blood samples were collected for biomarker (oxidative stress and DNA damage) and haematological analyses. The samples were digested using the microwave destruction technique. The metal analyses were carried out using ICP-MS. Oxidative stress enzymes (reduced glutathione content and catalase activity) were analysed in plasma samples and DNA damage was evaluated in red blood cells using the average base-pair length comparisontechnique. Haematological studies were done on the blood samples. The results were compared between the sites and surveys. The levels of stress correlated well with the levels of metals in the feathers. Sites with higher metal levels had higher levels of organism stress. Thus the study showed that the feathers can indeed be used in biomonitoring. Internationally there is a trend to incorporate Ecological Quality Objectives (EcoQOs) into legislation, especially when dealing with metal contamination. Within the framework of EcoQOs developed for birds the monitoring of contaminants forms a specific category of EcoQOs. However, due to a lack of available data, Reference and Target Levels still need to be set. The development of EcoQOs is especially important at this stage in South Africa. The recently promulgated National Biodiversity Act (10 of 2004) specifically provides for the preparation of conservation plans for identified ecosystems that are important because of their goods and services that they provide. Since there is no management tool available at present to develop a suitable management plan, the setting of EcoQOs that are in line with international standards and practices will be of immeasurable value to implementing the Act. Feathers from museum specimens were used to determine the Reference Levels for the various metals in the feathers. The Target Levels were calculated from the Reference Levels. These were compared to the Current Levels and the EcoQOs were determined for the metal levels in the feathers in weaver in Gauteng, South Africa. / Prof. V. Wepener